In addition to the color tests, measurements of rod and cone thresholds are made on some patients, particularly those beginning or receiving medication for lupus erythematosus or rheumatoid arthritis. Patients from studies on diabetic and sickle cell retinopathy and their age-matched normal controls are given four kinds of color tests. Some of the tests are repeated at later dates for confirmation of findings or possible correlation with changes in the disease state Tests were conducted on 243 patients, including some normal controls during the year.